Counties in Indiana by share of days with good air quality (US EPA AQI)

Jasper County had the highest share of days with good air quality (US EPA AQI) of 42 counties in 2002, at 100%. Marion County had the lowest, at 7.9%. The median was 45.6%. Source: EPA.

Highest100Jasper County

Lowest7.9Marion County

Median45.642 counties

Map of counties, 2002

Under 31
31 to 41
41 to 46
46 to 52
52 to 88
88 and over
No data

%, 2002. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2002

%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2002 (%)	Change on 2001
1	Jasper County	100	0 pts
1	Wayne County	100	0 pts
3	Daviess County	98.4	-1.6 pts
3	Putnam County	98.4	+0.1 pts
5	DeKalb County	91.9	-5.6 pts
6	Perry County	88.5	+36.9 pts
7	Gibson County	88.2	-2.5 pts
8	Whitley County	88.1	-11.9 pts
9	Wabash County	75.7	-3.6 pts
10	Knox County	62.6	+0.9 pts
11	Porter County	60.5	+0.9 pts
12	Huntington County	56.8	-4.4 pts
13	Hamilton County	53	-1.1 pts
14	Hancock County	51.9	-2.2 pts
15	Hendricks County	51.7	-2.4 pts
16	Posey County	49.1	-6.8 pts
17	Carroll County	47.3	-15.8 pts
18	Jackson County	47	-9.8 pts
18	Johnson County	47	-6.1 pts
20	Floyd County	46.6	-4.6 pts
21	Shelby County	46.4	+1.6 pts
22	Boone County	44.8	-9.8 pts
22	Warrick County	44.8	-6.6 pts
24	Greene County	44.3	-2.3 pts
25	LaPorte County	43.4	-1.6 pts
26	Delaware County	43.3	+0.7 pts
27	Morgan County	43.2	-7.6 pts
28	Elkhart County	41.5	-16.4 pts
29	Vanderburgh County	40.8	-20 pts
30	Vigo County	37	-2.3 pts
31	Madison County	36.2	-1.4 pts
32	Clark County	35.6	-4.7 pts
33	Washington County	33.6	-8.8 pts
34	St. Joseph County	32.3	-29.3 pts
35	Allen County	32.1	-30.1 pts
36	Tippecanoe County	26.6	+0.7 pts
37	Howard County	24.4	-8 pts
38	Spencer County	24.1	-60 pts
39	Henry County	23.7	-9.3 pts
40	Dubois County	20.2	-11.4 pts
41	Lake County	12.1	+1.7 pts
42	Marion County	7.9	-5.5 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 11 counties with data in other periods have no value for 2002 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts (Counties in Indiana by share of days with good air quality (US EPA AQI), 2002) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Indiana by share of days with good air quality (US EPA AQI), 2002. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in Indiana by share of days with good air quality (US EPA AQI), 2002. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Indiana by share of days with good air quality (US EPA AQI), 2002 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_indiana_by_2002,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Indiana by share of days with good air quality (US EPA AQI), 2002}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}

RIS

TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Indiana by share of days with good air quality (US EPA AQI), 2002
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/indiana-counties?period=2002.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -

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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Jasper County, with 100% in 2002, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Marion County, with 7.9% in 2002.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 11 counties have no value for 2002 and are not ranked.